Journal of the Atmospheric Sciences: Recent submissions
Now showing items 2841-2860 of 13215
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Local Mass Conservation and Velocity Splitting in PV-Based Balanced Models. Part II: Numerical Results
(American Meteorological Society, 2007)The effects of enforcing local mass conservation on the accuracy of non-Hamiltonian potential-vorticity- based balanced models (PBMs) are examined numerically for a set of chaotic shallow-water f-plane vortical flows in a ... -
Sources and Sinks of Available Potential Energy in a Moist Atmosphere
(American Meteorological Society, 2007)Available potential energy (APE) is defined as the difference between the total static energy of the atmosphere and that of a reference state that minimizes the total static energy after a sequence of reversible adiabatic ... -
The Dynamics of Idealized Convection Schemes and Their Effect on the Zonally Averaged Tropical Circulation
(American Meteorological Society, 2007)In this paper, the effect of a simple convection scheme on the zonally averaged tropical general circulation is examined within an idealized moist GCM to obtain broad classifications of the influence of convection on the ... -
Interpreting the Opposition between Two Block-Onset Forcing Mechanisms
(American Meteorological Society, 2007)The opposition between two block-onset forcing mechanisms, previously identified in midtropospheric analyses over the Southern Hemisphere midlatitudes, is analytically interpreted with an idealized model. These mechanisms ... -
Local Mass Conservation and Velocity Splitting in PV-Based Balanced Models. Part I: The Hyperbalance Equations
(American Meteorological Society, 2007)This paper considers stratified and shallow water non-Hamiltonian potential-vorticity-based balanced models (PBMs). These are constructed using the exact (Rossby or Rossby?Ertel) potential vorticity (PV). The most accurate ... -
An Evaluation of Microphysics Fields from Mesoscale Model Simulations of Tropical Cyclones. Part I: Comparisons with Observations
(American Meteorological Society, 2007)This study presents a framework for comparing hydrometeor and vertical velocity fields from mesoscale model simulations of tropical cyclones with observations of these fields from a variety of platforms. The framework is ... -
The Local Structure of Atmospheric Turbulence and Its Effect on the Smagorinsky Model for Large Eddy Simulation
(American Meteorological Society, 2007)Phenomena such as large-scale shear, buoyancy, and the proximity to the ground surface significantly affect interactions among scales in atmospheric boundary layer turbulent flows. Hence, these phenomena impact parameters ... -
A Three-Dimensional Wave-Activity Relation for Pseudomomentum
(American Meteorological Society, 2007)A three-dimensional, nonhydrostatic local wave-activity relation for pseudomomentum is derived from the nonhydrostatic primitive equations in Cartesian coordinates by using an extension of the momentum?Casimir method. The ... -
Resolving Convection in a Global Hypohydrostatic Model
(American Meteorological Society, 2007)Convection cannot be explicitly resolved in general circulation models given their typical grid size of 50 km or larger. However, by multiplying the vertical acceleration in the equation of motion by a constant larger than ... -
The Interaction of Katabatic Flow and Mountain Waves. Part II: Case Study Analysis and Conceptual Model
(American Meteorological Society, 2007)Via numerical analysis of detailed simulations of an early September 1993 case night, the authors develop a conceptual model of the interaction of katabatic flow in the nocturnal boundary layer with mountain waves (MKI). ... -
Generalizing Cloud Overlap Treatment to Include Solar Zenith Angle Effects on Cloud Geometry
(American Meteorological Society, 2007)Shortwave radiative transfer depends on the cloud field geometry as viewed from the direction of the sun. To date, the radiation schemes of large-scale models only consider a zenith view of the cloud field, and the apparent ... -
A Seasonal Climatology of Rossby Wave Breaking in the 320–2000-K Layer
(American Meteorological Society, 2007)Differential advection in Rossby waves can lead to potential vorticity (PV; P) contours on isentropic surfaces folding over in latitude (Py < 0) in a process called Rossby wave breaking (RWB). Exploring the properties of ... -
Observational Study of the Entrainment-Mixing Process in Warm Convective Clouds
(American Meteorological Society, 2007)Thermodynamical and microphysical measurements collected in convective clouds are examined within the frame of the homogeneous/inhomogeneous mixing concept, to determine how entrainment-mixing processes affect cloud droplets, ... -
The Triggering of Orographic Rainbands by Small-Scale Topography
(American Meteorological Society, 2007)The triggering of convective orographic rainbands by small-scale topographic features is investigated through observations of a banded precipitation event over the Oregon Coastal Range and simulations using a cloud-resolving ... -
Circulation Regimes due to Attractor Merging in Atmospheric Models
(American Meteorological Society, 2007)From a dynamical systems theory perspective, the mechanisms of atmospheric regime behavior in a barotropic model, a pseudobarotropic model, and a baroclinic three-level model, where all of them show quite realistic regimes, ... -
Meridional and Downward Propagation of Atmospheric Circulation Anomalies. Part I: Northern Hemisphere Cold Season Variability
(American Meteorological Society, 2007)The Northern Hemisphere cold season circulation anomalies are diagnosed in a semi-Lagrangian ?PVLAT (potential vorticity surfaces as latitudes) coordinate by following contours of the daily potential vorticity (PV) field ... -
An Idealized Two-Dimensional Framework to Study the West African Monsoon. Part I: Validation and Key Controlling Factors
(American Meteorological Society, 2007)An idealized vertical?meridional zonally symmetric model is developed in order to recover a July typical monsoon regime over West Africa in response to surface conditions. The model includes a parameterization to account ... -
A Lagrangian Trajectory View on Transport and Mixing Processes between the Eye, Eyewall, and Environment Using a High-Resolution Simulation of Hurricane Bonnie (1998)
(American Meteorological Society, 2007)The transport and mixing characteristics of a large sample of air parcels within a mature and vertically sheared hurricane vortex are examined. Data from a high-resolution (2-km horizontal grid spacing) numerical simulation ... -
Tropical Stationary Waves in a Nonlinear Shallow-Water Model with Realistic Basic States
(American Meteorological Society, 2007)The nonlinear shallow-water equations are used to study the tropical stationary wave response to steady thermal forcing near the equator in earthlike zonally symmetric basic states. A thin (200 m) fluid layer is superimposed ... -
A Gray-Radiation Aquaplanet Moist GCM. Part II: Energy Transports in Altered Climates
(American Meteorological Society, 2007)A simplified moist general circulation model is used to study changes in the meridional transport of moist static energy by the atmosphere as the water vapor content is increased. The key assumptions of the model are gray ...